This invention relates generally to lighting fixtures and fire detectors, and more particularly to a combined light fixture and fire detector for simultaneous mounting on a recessed electrical outlet box.
The concept of combining a lighting fixture and fire detector has been shown in at least two patents, specifically, U.S. Pat. Nos. 4,090,178 to Norris and 4,255,746 to Johnson, et al. The patent to Johnson, et al. discloses a home safety unit which includes an emergency light system and a fire detection system, wherein the lighting fixture is fixed to the outside of a housing and the fire detection system is mounted within the same housing. The smoke detector and light fixture disclosed in the Norris patent is similar in that the fire detector is concealed within a housing. An alternate embodiment disclosed in the Norris patent situates the smoke detecting element of the smoke detector at a distance from the electrical box by means of an electrical conduit, thereby requiring an additional hole to be cut in the ceiling.
The shortcomings of the fixtures disclosed in the Johnson, et al. and Norris patents should be readily apparent to one of ordinary skill in the art. These shortcomings include the requirement that additional holes be provided in the housing to permit detection of smoke by the fire detecting element. Further, since the smoke detecting means is mounted within the housing, maintenance and repair of the same becomes difficult, as this would require removal of the lamp diffuser, the lamp and the housing itself. More importantly, such maintenance and repair can only be safely accomplished by cutting off the main power source and disconnecting the leads of the fixture from the leads of the electrical box, so as to gain access to the smoke detection means.
Further, electrical devices of this type must meet certain minimum standards under the applicable building and electrical codes, or the more stringent standards of an independent testing organization, as is desirable when placing such a device into the commercial marketplace. Such standards normally require heat and electrical tests at different points about the lighting or other electrical fixture, at least one of such points exists within the electrical outlet box or within the housing of the type shown in the aforementioned patents. Thus, placement of the fire detecting means within a housing will have an adverse affect upon these heat and electrical tests, as more heat will be generated and trapped therein.
In providing fire safety systems, it is often desirable to provide fire detectors having a heat sensing element in addition to or in place of a smoke detecting element, since the heat generated by a fire might be detected before the smoke. The devices disclosed in Norris and Johnson, et al. do not provide an adequate design to include heat sensing elements because the heat generated within the housing and electrical box might trigger the heat sensing element under normal operating conditions.
As building and fire codes become more stringent, it is desirable to provide a combined light and fire detector fixture which can be directly mounted onto a recessed electrical outlet box and cures the above-noted shortcomings of the prior art fixtures.
Accordingly, the present invention provides a single fixture for mounting a fire detector and a lamp holder to a single recessed electrical outlet box, which single fixture can be readily mounted in residential dwellings by homeowners or in any other setting, new or old, by an experienced builder or electrician. The use of conventional lighting fixtures and fire detectors facilitates the commercial practicability underlying the present invention.